Perfluoro-3-aminodiaziridine and its preparation



United States Patent Ofi I 3,345,359 PERFLUORO-S-AMINODIAZIRIDINE AND ITS PREPARATION William Charles Firth, Jr., Stamford, Conn., assignor to American Cyauamid Company, Stamford, Conn., a corporation of Maine N Drawing. Filed June 28, 1962, Ser. No. 207,153 Claims. (Cl. 260-239) This invention relates broadly to a new and useful fluorinated compound, more particularly perfluoro-3- aminodiaziridine, and to a method of preparing the same. Still more particularly the invention is concerned with the production of fluorinated compounds including perfluoro- 3-aminodiaziridine by bringing perfluoroguanidine into reactive relationship with an alkali-metal (e.g., rubidium, cesium, potassium, etc.) fluoride or a mixture of such fluorides in any proportions.

Perfluoroguanidine, the formula for which is and hereafter for brevity often referred to as PFG, can be obtained, for example, by the fluorination of biguanide using the so-called fluid-bed technique as is more fully described in the copending application of Simon Frank and Douglas M. Meyers, Ser. No. 195,023, filed May 11, 1962, and assigned to the same assignee as the present invention. In the method there described 1,1-difluorocyanamide is produced and, ordinarily also, perfluoroformamidine and perfluoroguanidine.

No pertinent prior art is known. Miller et al. [1. Am. Chem. Soc., 83, 1767-8 (1961)] disclose that reaction takes place between cesium fluoride and perfluorodienes at moderate temperatures in the absence of a solvent to yield perfluorodialkylacetylenes.

The properties of a typical sample of perfluoroguanidine are given in Table I.

TABLE I Molecular weight (by gas density): Ca1cd., 149; found, 14l=!;5. Bolling point: 2;l=2 O. by extrapolation from log Pmm=8.07%

F nuclear magnetic resonance spectrum:

(in p.p.m.) Appearance Area Ratio Assignment NF -47.2 in, broad 2 *F NC- NF 42.3 in, broad 2 *F9NC- F .20.5 w, broad 1 0:

Indicates group considered. **m=medium; w=weak.

ice

there are four kinds of bonded fluorine present in the compound at fields suggestive of NF NF (two groups) and CF. The NMR spectrum, together with the infrared spectrum, suggests that the cyclic diaziridine structure is the most reasonable of the three structures, one of which is that shown in Formula II, and the others of which are as follows:

N La

The infrared spectrum of the isomer obtained by the method of this invention is consistent with these assignments. The isomer has only one C-F band at this characteristic low frequency. It also has a characteristic band at about ll.l,u., which it seems reasonable to assign to the NF group. Furthermore, the isomer has a more complex spectrum in the NF region than does the cyclic diaziridine obtained by the isomerization of perfluoroformamidine using the same general technique and isomerization catalyst, as one would predict from the respective structures.

The F nuclear magnetic resonance spectrum of the isomer of PEG obtained by the method of this invention is given in Table H.

' *About 3 mole percent.

The mass spectrum of the isomer of PFG resulting from the method of this invention is shown in Table 111.

TABLE Ill-MASS SPECTRUMPQ FGTHE ISOMER (PFADA)OF M/e Pattern Possible 0 ation 97 11 ON 2 F 83 45 CNFS 69 25 CR; 64 91 CNFa 52 13 NF 1 50 21 CF; 45 20 CN F 33 26 NF 31 CF 28 69 N 20 19 HF 19 6 F Any suitable means can be employed in bringing the perfluoroguanidine reactant into contact with the alkalimetal fluoride reactant. Good results have been obtained by bringing the PFG into contact with the alkali-metal fluoride while the former is in liquid state and then allowing it to reach ambient temperature (room temperature), e.g., 2030 C., or even about 40 C, Thus, the temperature of reaction may range, for example, from about 132. C. to ambient temperature.

If desired, gaseous PFG can be passed upwardly or downwardly through a bed of alkali-metal fluoride in Example 1 A 27-ml. reactor was charged with 5.0 g. of anhydrous, finely divided rubidium fluoride and 0.7 mmole of PFG.

divided state or form. Or, it may be passed through a 5 After tanding for 3 hours at -80 C., the products plurality of inlet ports or openings whereby the gaseous were separated from the rubidium fluoride (without PFG reactant is introduced at a plurality of points into g) by bnlb-te-bnlb distillation and measured h a bed of the alkali-metal fluoride contained in a suitable product gases from each run were condensed at -132 C. reactor, and the gaseous roducts of the reaction are (thereby avoiding the possibility of explosions sometimes withdrawn from the reactor along with any unconverted encountered when condensed at 196 C.), and were PFG. The reaction can be carried out continuously, then used at the next higher temperature. The reaction semi-continuously or by batch technique, and at atmosconditions and the mmoles of gas at the start and the end pheric or superatmospheric pressure. of each 3-hour period are shown below:

The alkali-metal fluoride may be of any suitable size or shape, for example in finely divided state such as of from 50 to IOO-mesh fineness; or in the form of larger Reaction Mmolesomas particles (coarser than SO-mesh), beads, pellets, etc.

The time of contact of the PFG reactant with the Time start End alkali-metal fluoride reactant can be varied as desired or hours as conditions may require depending, for example, upon such influencing factors as, for instance, the design of 3 the reactor; whether or not the operation is continuous, 3 :33 8:23 3:2; semi-continuous or batch; the size, shape, surface area, etc., of the alkali-metal fluoride; temperature and/or pressure at which the reaction is effected; and other influencing conditions. For example, when the reaction is Infrared examination of the condensate from carried out continuously with the PFG in the gaseous the last of the three time showed mostly some state the time of contact may be from less than a minute peiflnoio'3'aniinedieliiidine carbon tetra- (e.g., about A minute) to 10 or 15 minutes or more. fluoride and an unknown P Y- In batch operations the contact time may range, for in- The Product of the reaetion was Stored in a stance, from 10 or 15 minutes to 24 hours or more. 6 i Teaet1".with of anhydrous, finely divided Usually it is advantageous that the alkali-metal fluoride rubidium fluoride for 3 hours at No Pressure p b in anhydrous (Substantially completely anhydrous) occurred during the reaction. Infrared analysis of the state. By anhydrous alone or substantially completely Product gas indicated the Presence of PFADA, anhydrous as used herein with reference to the alkalihaien tetreflnoiide, tii$(difin0f0aniin0)flllofolnethane, metal fluoride reactant is meant one which contains no and P y Shine more h a trace f Water or h amount f water that In another series of runs, the details of which are given might be present in the commercial product. The amount in Table IV, a y reactor pp p volume to give of water should not be such as would adversely affect the Pressures Shown in Table was charged in a y the course of the reaction or the constitution of the reac- 40 box with of anhydrous, finely divided rubidium i d t, fluoride, evacuated and then PFG (amount shown in The amount of the alkali-metal fluoride ingredient or Table was condensed in with a bath- The reactant with respect to the PF G reactant is not critical, reactor was isolated from the Test of the Vacuum System and may be varied as desired or as conditions may reand allowed to warm to room temperature quire. The alkali-metal fluoride functions as a conversion Over 10 to 15 niinutes- After the reaction time Shown in catalyst. the table, the total product .gas was measured and sep- If desired, the PFG reactant may be diluted with an arated i o C- a l96 C. condensates. inert material, e.g., an inert carrier material in gaseous During the fractionation the 196 C. trap was pumped or other state. Examples of such diluents that can be used On to r v a y n nond nsable gases. The '196 C. are, for instance, helium, argon, nitrogen, neon, bis(did 5 e Was OWn by infra-red and mass spectrofluoroamino)difluoromethane, etc. The concentration of metric analysis to be mostly a mixture of carbon tetrafluothe PFG in the diluent can be varied as d ired 01' a ride, difluorodiazine (both isomers) and carbon dioxide. conditions may require, e.g., from 1:99% by volume of The --132 C. c n nsate Was mostly perfluOr0-3-amino- PFG to 99:l% by volume of the diluent mat rial, diaziridine, but Cady et a1. fractional co-distillations In order that those skilled in the art may better under- [G. H. Cady and D. -P. Siegworth, Anal. Chem.,, 31, 618 stand how the present invention can be carried into effect, (1959)] were necessary to remove both higher and lower the following examples are given by way of illustration boiling fractions. and not by way of limitation. All parts and percentages The reaction conditions and results of the runs are are by weight unless otherwise indicated. summarized in Table IV.

TABLE IV Reac- Calcution RbF, lated Mmoles Mmoles C. Conden- -132 C. -196 C. Example Time, grams PFG PFG Product densate Condensate Condensate hrs. Pressure, 1

2 4 5.0 9 0.11 0.12 Undetermined (PFADA+N F ,andprobably 0E4 plus an unknown impurity).

3 3 5.0 117 0.93 d0 0.65mmole 0.24mmole.

4 3 5.0 620 0.89 1.0 None 0.56mmole 0.30mmole.

Largely perfluoro-3-aminodiaziridine (PFADA). "Largely CF,, 00;, NgFg, all isomers).

In Table V are given the reaction conditions and the results of three other runs wherein PFG was reacted with an anhydrous, finely divided alkali-metal fluoride, specifically rubidium fluoride (Example 5), cesium fluoride (Example 6) and potassium fluoride (Example 7). The apparatus and procedure were essentially the same as that employed in the runs of Examples 2, 3 and 4 and which were described in the portion of this specification immediately prior to the said examples.

acting together perfluoroguanidine and an alkali-metal fluoride.

3. A method as in claim 2 wherein the alkali-metal fluoride is rubidium fluoride.

4. A method as in claim 2 wherein the alkali-metal fluoride is cesium fluoride.

5. A method as in claim 2 wherein the alkali-metal fluoride is potassium fluoride.

6. A method as in claim 2 wherein the reaction mass TABLE V Grams Mm. Pres- Example Mmoles Alkali-Metal Reaction sure in Increase or Decrease Products of PFG Fluoride Time Reactor in Mmoles of Gas (Caled.)

0. 18 5.0 (RbF) 13 min.... 15 No change PigiglgA; PFG; some C-F absorption at 0.26 1.0 (CsF) 5% hrs. do Largely PFADA; small amounts of unidentified materials. 0.70 5.0 (KF) 18 hrs 60 0.05 mmole inerease PFADA and unidentified materials.

The reactor was allowed to warm slowly (over a period of 5% hours) from 30 C. "In Example 7, PFG was admitted as a gas to the evacuated reactor containing the potassium fluoride.

The following example shows one use of perfluoro-3- aminodiaziridine, more particularly as an intermediate in chemical synthesis.

Example 8 About 0.2 mmole of PFADA was reacted at room temperature with 1 ml. of 100% H 80 in a Pyrex reactor to yield carbonyl fluoride and small amounts of silicon tetrafiuoride, carbon tetrafluoride and difluoroamine.

In addition to the foregoing example it may also be mentioned that PFADA is highly reactive as shown by its complete decomposition to unidentified compounds after one month in a Pyrex nuclear magnetic resonance tube (i.e., an NMR tube) containing Freon 11.

PFADA is an explosive. Thus, when a purified sample of PFADA was being condensed at --196 C. into an NMR tube, the material exploded.

PFADA also is useful as an oxidizer and as an intermediate in the synthesis of other oxidizers. Such oxidizers are particularly useful in rocket-propellant compositions.

I claim:

1. Perfluoro-3-aminodiaziridine.

2. The method of preparing fluorinated compounds including perfluoro-3-aminodiazi1'idine which comprises reis at a temperature ranging from about -132 C. to ambient temperature during the reaction period.

7. The method of preparing fluorinated compounds including :perfluoro-3-aminodiaziridine which comprises reacting together perfluoroguanidine and an alkali-metal fluoride at a temperature ranging from about -132 C. to ambient temperature during the reaction period; and isolating pe1fluoro-3-aminodiaziridine from the resulting reaction mass.

8. A method as in claim 7 wherein the alkali-metal fluoride is rubidium fluoride.

9. A method as in claim 7 wherein the alkali-metal fluoride is cesium fluoride.

10. A method as in claim 7 wherein the alkali-metal fluoride is potassium fluoride.

References Cited UNITED STATES PATENTS 3,257,381 6/1966 Meyers et a1. 260239 ALTON D. ROLLINS, Primary Examiner. OSCAR R. VERTIZ, Examiner.

J. W. WHISLER, Assistant Examiner.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,345,359 October 3, 1967 William Charles Firth, Jr.

It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 1, lines 20 to 22, the formula should appear as shown below instead of as in the patent:

column 2, TABLE II, last column, the first formula should appear as shown below instead of as in the patent:

same table, second column, line 4 thereof, for "2, broad" read w, broad column 4, lines 34 and 35, for "carbaron read carbon columns 5 and 6, TABLE V, in the first footnote, for "from -30 C." read from -l32 C. to -30 C.

Signed and sealed this 26th day of November 1968.

(SEAL) Attest:

EDWARD M.PLETCHER,JR. EDWARD J. BRENNER Attesting Officer Commissioner of Patents 

1. PERFLUORO-3 AMIONDIAZIRIDINE.
 2. THE METHOD OF PREPARING FLUORINATED COMPOUNDS INCLUDING PERFLUORO-3 AMINODIAZIRIDINE WHICH COMPRISES REACTING TOGETHER PERFLUOROGUANIDINE AND AN ALKALI-METAL FLUORIDE. 